Breechblock lock for firearms



12 Sheets-Sheet 1 lmlmnmf C. E. SIMPSON BREECH BLOCK LOCK FOR FIREARMS June 5, 1951 Filed June '7, 1946 June 5, 1951 c, E, slMPsQN 2,555,379

BREECH BLocx Loox Fox FIRE/mms File June fr, 194e 12 sheets-sheet 2 NN J lll Wmv NN\ h D6 um Y K ElurEncQE lin-L]:5mn

MXMWMM June 5, 1951 c. E. slMPsoN BREECH BLOCK LOCK FOR FIREARMS 12 Sheets-Sheet 3 Filed June 7, 1946 1111.]35 IIIIL Y ElnDEILuEE 5 IJIUHI gg M Ww RWM@ @rw WMM .ARINMMWMMWWM Mowlhwmh u @M r l! m A mamy/MM June 5, 1951 c. E. slMPsoN BREECH BLOCK LOCK FOR F-IREARMS Filed June 7, 1946 12 Sheets-Sheet 4 eea 2/9 207V nFun@ 5, 1951 l C, E, slMPsoN n 2,555,379

BREECH BLOCK LOCK FOR FIREARMS Filed June 7, 1946 12 Sheets-Sheet 5 EluTEl-L I: E E 'll'l-.ELFE :mi

June 5, 1951 C, E, slMpsQN 2,555,379

' BREECH BLOCK LCK FOR FIREARMS Filed June 7, 1.946 l2 Sheets-Sheet 6 Gluren-1: E.- 5in-LFE. :l1-1

@WM M www @Lv LQNII June 5, 1951 c. E. slMPsoN BREECH Locx Loox Foa FIRE/mus 12 Shee'tS-Sheet 7 Filed June 7, 1946 June 5, 1951 c. E. slMPsoN O BREECH BLOCK LOCK FOR FIREARMS 12 sheets-sms Filed June 7, 1946 |11 :LINE rune E mp En 33? M r2-ffm, am

June 5, 1951 C, E, slMpsoN 2,555,379

BREECH BLOCK LOCK FOR FIREARMS Filed June '7, 1946 12 Sheets-Sheet 9 Fig-E- Fi5 .51

FIS-EE- 427 vf. MAM

June 5, 1951 c. E. SIMPSON 2,555,379

BREECH BLOCK Lcx FOR FIREARMS Filed June 7, 1946 12 Sheets-Sheet 10 I Y Syvum/VM llmDEl-u: E E in-LPE. :111

June 5, 1951 c. E. slMPsoN 2,555,379

BREECH BLOCK LOCK FOR FIREARMS Filed June 7, 1946 12 Sheets-Sheet l1 E23 WMWW/ig .im 5, 1951 C, E, SMPSON 2,555,319

BREECH BLOCK LOCK FOR FIRERMS Filed June '7, 1946 12 Sheets-Sheet 12 F'if .E|1

JOE

Patented June 5, 1951 Clarence E-. Simpson, Springeld, Mass., assignor to thefUnited. Statesof America as represented by the Secretary'of- War ApplicationJune 7; 1946, Serial No. 675,124

1-2 Claims. (Cl. 823-186) (Granted under theact of- March 3. 1883, as amended.'v April 30, 1928; 370 O. G. 757) The invention described herein. maybe manuffactured and used by. or for the. Governmentfor governmental purposes, Without thepayment t me of. any. royalty thereon.

This invention. relatesto a. firearm of. the semiautomatic type.

Most firearms of,` the semi-automatic. type. which utilize a comparatively large caliber high power cartridge are of rather ponderousand cornplicated construction. and generally are provided with. a fixed barrelprecluding the possibility of replacing` such barrellinfthefneld. Obviously such irearms cannotbe readily transported and further these-nrearms .would require .afcomparatively large mount co-support the weight of such lire-` arm. `Another disadvantage with mostrearms.

of" thetype above mentioned is that an excessively long recoilmovernent of theboltisrequired for the ammunition-feedingv cycle. lurthernfiore9 the ammunnitionputilized. in such. firearms isvgen-V erally not conveniently.. carried in easily handled. clips thus making loadingl of. the firearm some.- vvhat cumbersome.

Accordingly, it isranobject of-thethis invention to provide. an improved. large` caliber; semi-auto.-

matic-r-marm having a comparatively short re.

Another` object of this inventionisto -provide an.

improved semi-automatic rearmi ladapted to utilize ammunition contained in conveniently handled strips, such ammunit-icnjbeing alignedv in the feedway by mechanica-lmeans` independent of the recoiling membersof'thefnrearm Another' object of this invention is to provide a large caliber militaryrearm thatreadily; disassembles into. two major. assemblies for ease in transporting.

Thespecic nature ofthe invention aswellas other objects and advantages thereof will clearly appear from a description of'a preferred embodimentas shown inthe accompanying drawings in which:

Fig. 1 is a longitudinal sectional -view of the rear-half of the'lrearm.

Fig. 2 isa side elevation-al view of the forward half*V of the rearm shown part-ly in-v cross-.section;

2y Fig. 3. is atonelevationalview ofthe rear half jof the firearm.

Fig.y 4 is. atonelevationalview of the forward half of'the rearm.

Fig.. 5 .is aleitside eleyational view of. the rear half oi the firearm.

Fig. 6. isaleftside.elevational-view of. the front half of the re'arm.

Fig., '7 isa. detailed view. shownpartlyin longi.-

tudinal section. of the rearmi withv the breech mechanism. inthe closed. position immediately after firing a cartridge.

Fig. 8 is zaview. similar tQFig... '7 butwith .the action and barrelV in the extremerecoiled posi.- tion.. .v

Fig. `9` is aview. similar to.. Fig.. Sbut with the.

barrel unlocked` from the breechiechanism andshown` nearly` imbatteryposition.

Fig. 10 is a view similar to Fig. 9 butwith the breechv block inthe bottom positiorronthe carrier withY around.contained inthe .breechblock readyv toenter` thebarrel. chamber ,as the breeclrt mech.- anism, goesintobattery..

Fig. 11 isa. side.I elevatonalview ofthe left hand side plate illustrated in an upside down position. showing. the various cuts` on the interior thereof'.

Fig. 12 is a cross sectional View takenfal'ong theline..I.2-I.2 of. Fig. 11.

Fig. 13 is a. cross Vsectional-view. taken along the line Lil- I3 OfiEig. 1l,

Fig. 14 isa. crosssectional view. taken along., the line VUl---Ul otFg. 1.1.

Fig. 15 is a side elevational view of theright. hand. side plate showing the various cuts on the interior thereof.

Fig. 16 is a crosssectionalview taken along the line I6--l6 of Fig. 15.

Fig. 17 is ,arear end. elevationalview. of the fire- Y Fig. 20.isan enlargedcross sectional view taken Y along the line 20`2|l of Fig. 19.

Fig. 21V is, a cross sectional. detail view. taken along. the. line 'l1-2|V ofFigs. l9..and'2.0.

Fig. 22, is a cross sectional view taken along y the line 2'2i-.22Lof Fig. 20..

Fig. 2.3v isp aside elevational detail View of the breech blqckshowinethe loxckinglugs onthe. SideV thereof.

Fig. 24 is a cross sectional view taken along the line 2li-24 of Fig. 23 showing the T-shaped rib on the inclined arm of the breech block.

Fig. 25 is a sectional view taken along the line 25-25 of Fig. 23.

Fig. 26 is a cross sectional view taken along the line 26-26 of Fig. 23.

Fig. 27 is an enlarged detail view shown in 1ongitudinal section of the sight mount elevating mechanism taken along the line 21-21 of Fig. 5.

Fig. 28 is a front end elevational view of the forward bottom plate.

Fig. 29 is a side elevational view of the feedway.

Fig. 30 is a side elevational view of the rear spacer.

Fig. 31 is an end elevational view of the rear bottom plate.

Fig. 32 is a top elevational view of the rear bottom plate.

Fig. 33 is a longitudinal sectional detail view of the breech mechanism retaining mechanism utilized for securing the breech mechanism in a partially retracted position.

Fig. 34 is a top elevational detail View of the sear releasing wedge-like member.

Fig. 35 is a top elevational view of the trigger.

Fig. 36 is a longitudinal sectional enlarged detail view of the sear release mechanism mounted on the rearm.

Fig. 37 is a cross sectional view taken along the line 31-31 of Fig. 36 showing the safety lock.

Fig. 38 is a detail view of the T-shaped plunger utilized in the sear release mechanism.

Fig. 39 is a top elevational view of the sear illustrating the sear tang.

Fig. 40 is a cross sectional view taken along the line 40-40 of Fig. 10 showing the T-slot in the carrier for mounting the breech block.

Fig. 41 is a side elevational detail view of the front spacer.

Fig. 42 is anenlarged detail view shown partly in longitudinal section of the barrel support illustrating the manner in providing clearance to facilitate removal of the barrel from the firearm.

Fig. 43 is a side elevational detail view of the operating slide.

Fig. 44 is an enlarged detail side elevational view showing the stop secured to the inclined arm of the breech block. Y

Fig. 45 is a detail fragmentary rear end view of the assembled breech block and carrier.

Fig. 46 is a fragmentary longitudinal sectional view of the assembled breech block and carrier illustrating the position of the ring pin and hammer. Y Y

Fig. 4'7 is an enlarged sectional view taken along the line IIT-41 of Fig. 18.

Fig. 48 is a top elevational view of the carrier slide.

Fig. 49 is a rear end elevational view of the barrel extension illustrating the locking lugs and guide ribs thereon.

Fig. 50 is a side elevational view of the right hand feedway mounting bracket.

Fig. 51 is a side elevational detail view of the cartridge stop pawl.

Fig. 52 is a side elevational detail view of the feedway retaining pin illustrating the locking notch thereon.

Fig. 53 is a side elevational detail view of the locking spring utilized to secure the cartridge strip actuating tape within its cylindrical housing.

Fig. 54 is an enlarged detail longitudinal sectional view showing the operating slide contacting the firing pin retracting lever utilized for rais- .the barrel.

withdrawn from the cartridge strip by a T-slot in ing the hammer from the ring pin to eliminate breakage of the ring pin tip when opening the action of the rearm.

The rearm to be described in more detail comprises essentially an open receiver having suitable ways on which is mounted'a breech block and breech block carrier. The barrel of the rearm is readily detachable from such rearm and is supported at the forward end of the receiver by a suitable barrel support. The barrel screws into a threaded barrel extension. In the closed or breeched position, the breech block and barrel extension are held in locked relation by suitable locking lugs. A hydraulic recoil and counterrecoil mechanism is contained within a cylindrical tube extending forwardly of the receiver to check the recoil and counter-recoil forces of the rearm.

The forward portion of the barrel rests in a front barrel support mounted on the end of the hydraulic cylinder tube. The cartridges are contained in strips which are fed into the feedway of the firearm and such feedway is mounted transversely across the top of the breech end of The cartridges are arranged to be the breech block. The cartridge strip is fed across the feedway by a spring actuated mechanism.

Referring to the drawings wherein similar characters refer to similar parts, there is shown in assembled relation in Figs. 1, 2, 3, 4, 5, and 6 a firearm embodying this invention. A receiver I is provided to support the elements `of the iirearm. The receiver I comprises two parallel side plates 2 and 3 separated at the rear and forward ends respectively by a rear spacer I and a front spacer 5. A rear bottom plate 6 and a forward bottom plate 1 are secured to the bottom edges of side plates 2 and 3 as will be presently described. The rear spacer 4 (Figs. 1 and 30) comprises a substantially rectangular block which has formed thereon an integral rearwardly projecting cylindrical boss 9. An axial hole I0 is provided in the boss 3 which passes through the block portion of spacer 4. The hole II) is of reduced diameter as shown at I0a where such hole emerges from the forward face of rear spacer 4. Boss 9 is provided with threads II on the outer periphery thereof to receive a buffer cap I2. Such buffer cap retains a buffer mechanism within hole I0 as will be later described. An integral vertical rib I3 is provided on each side of spacer 4 (Figs. 3 and 30) which engages corresponding vertical grooves I4 provided on the rear inside edge of each side plate 2 and 3. The side plates 2 and 3 are secured to the rear spacer 4 as by screws I5.

As previously mentioned, the forward ends of side plates 2 and 3 are secured in spaced relationship by the front spacer 5 (Figs. 4 and 41), such spacer comprising a substantially rectangular block. An integral cylindrical boss I8 extends forwardly from the front face of spacer 5, the exterior of which is provided with threads I9 for a purpose to be described. An axial hole 20 is provided in boss I8 and extends through spacer 5 for a purpose to be described later. Front spacer 5 is also provided with tw-o oppositely disposed, integral, vertical ribs I1 which engage suitable vertical grooves 2I on the inside surfaces of side plates 2 and 3. Side plates 2 and 3 are secured to the front spacer 5 as by screws 22.

The rear bottom plate 6 (Figs. 1, 3l and 32) essentially comprises a long narrow channelV shaped .i member. On each aside-fof :rear :bottom plateA 16 there .is .iprovidedan fintegrallhorizontal projecting "rib .-23. Ther-ib l' 23 engages lcorresponding horizontal grooves 24 inJside` plates -52 and 3 to securelyzpositionsbottom plater @tosuch side;.plates. `The forward end fof `rear"bottom plate-6 slopesizdownwardlyas lsfhowneat'25': (Figs. lfand 31). .".An opstanding'flug L26fiswcentrally provided ron the downwardly inclined lendif-Bloot rear bottom iplate e6 :and a downwardlyV sloped -cam surface 12'! 'ris eprovided lon`- the forward` face if of such lug. for: :a .purpose to bei described. Somewhat 'to therear lof the downwardly sloped ``end .fof rearobottom :plate .6, two iritegral,=inwardly projecting, :oppositelyfdisposed lugs` 28 are provided i 'topivotally mount uaftcarrier frlajtch |86- to be flater described. A transverse: hole 129fis provided'linfeach lug l28, such holes-being counterbored on theirinner endsas-shownat. "'BotvThe forward bottoml. plate` Il is likewise 'a channel 'shaped member. ALA. suitablefintegralfrhorizontal ribv 32 (Figi 28) #extending thelleng'th of bottom plate?. issprfovidedvon each side of suc-h bottom plate .and Sengages suitable horizontal grooves 33 ontherbottom. edge of'fea'ch side plate 2 andl3` (Figs..11.and 1:15)."3Botto1n plate'lis secured to'side plates 2 Aan`d-3 bys'crews 34.

*Near'the upper edge of each-side -plate Zand 3, there `is .provided La 'longitudinal grooveelike guideway 35 to slidably-support a'barrel extension |56 A'to v'be described. The-forward'` portion 35a of leach guid'ewayf35lis cut'through to'the top 'of side plates 2 .and-3 Sto permita-the barrel extension to..be readily removed -from such side-plates in a manner to be later described. *Somev'fhat-below the longitudinal -guideway 35Yan' integral longitudinal rib36 is provided-oneachrof the side plates "2. Land 3 Vand terminates just short "of VAthe forward end of suchfside plates. Nearfthe lower edge of side platee Aunderneath 'rib 36 aflongitudinal T-slot'l fis provided Ato s'lidablymo'unt an operating slide |15 to be described.

A tubular -member 38 `internally threaded at its rear end -is horizontallyisecuredtothe'boss 8 of frontspacer 5*'by'screwing such tube onto'threads I9 of boss |78. Thetube whousesa recoil spring and a hydraulic recoil'and'countererecoil mecha- Y,

nism` which is fully Adescribed fin my patent application,"Serial No. 439,658, Afiled .April 20,1942, now U. -SrPatent No; 21364;'103.

'Ilo support a barrel j5|! ofthe rearm, a'front barrel bearing supports V(Figs. 2 and -.4'2),..is secured tothe forward end oftube J38h51 threads 46. "The front barrel support39 .comprises *a cylindrical'end cap4| and. an `integral upwardly projecting lug42. A longitudinal holel43 is'provided in lug'42 to admit the forward end of barrel 5U. To facilitate insertion .andwithdrawal of barrel 58 from front barrel .support 39,the upper rear surface of hole43`is .enlarged and-tapered slightlyes shown at-44while thelowerfopposite surfacef'of hole 43 is'flikewise slightlyenlarged. .165

Hence, barrel may beraised` 6V by'ithe .remaining icylindricalsportion' 46 'and fll'l dfifholeij43.

:In the bottomof' 'frontfspacer `5 there .ispro- VidedacentralIy located vertical threadedhole 48. A stop 49 (Fig. 2) 'comprising a cylindrical head `portion 5|sand-'a stem'portion 52 is inserted in hole 4'8'awith the head portionfupper-most. A raised arcuate rib'53 is providedon the rendfof head `portion 5| which engages .a shoulder '54 formed by` a .reduced diameter section of: ahydraulic cylinder which .-feXtends forwardly within tube `:38. A spring'56 surrounds .stem portion52 `ofi-stops!) and is retained vthereon'loy afgland'lscrewed into the :bottom of hole 48. A lever 58 is pivotally mounted Von the .lower vend of: stem portion '52-of stop'll by a pin 59, the forward end Aof `leversfEIi being'bifurcated to `permit such zmounting. Lever 58 normally rests againstfglan'd 51. A pin '6|lfprojecting radially frOmfthe.cylindrical'head portion 5|`of stop149 engages a:vertical .slot"6| vprovided inthe Vrear wall lof hole-'48 to .prevent rotation of'stop '49. Thus lever 58 is maintainedin the position shown inFig;12.

`A carrier. actuating: rod 62 :projects out 'of the rearr-endof hydraulic cylinder55 and is ifconnected toa carrier slide 63 (Fig. 48) asbythreads 64. v.The carrier .slide. 63 essentially comprises a long narrow rectangular `frame-like member and such slide rests .on top of the `integral ribs 3601 side plates 2.and 3. Carrier slide 63 is connected toa'breechblockcarrier |25 to actuate such carrier ineJ mannerfto be later described.

vA buller mechanism '65 .(vFig. 1) is contained within tthe hole Il! vin rear spacer 4. Buffer mechanism 65 comprises mainly two telescoping tubes v66 and 61, the tube'i being slidably contained withintube .'61 land `a spring 68 being contained withinvtube 66. Tube 61 has one Send 69 of reduced: `diameter which `projects forwardly throughzaireduced` diameter forward fendA portion T6 'of hole V|0. .The rearendof tube 61'is conica'lly beveled as shown'at 1|. A conically shaped head Y'|21'having` a :slope corresponding to that shownzzatl `isprovided on they rear end oftubel 66. buferring 13 having a substantially conically shaped Vcross :section surrounds buffer tube 66 and rests/:between the conicaly 'shapedfhead |2vofvsuch tubeand the :conical end 1| of tube 61. v'Ihespringfz68 is retained within tube I66 by cap I2 which is screwed onto threads of rear spacer `4. Azstud 14 mounted inthe center of buffer cap |.2 'snugly engages the interior of spring 68 to..keep.'such spring iin 4alignmentwith the vaxis ofsfbuier mechanismi. A'boss 'l5 is integrally?formedonfcap I2 and projects out- Wardlyatfright angles to the axis of the rearm onLwhich'is detachably mounted Ya shoulder'rest (not shown).

'Breech ".b1ock'14llcomprises a substantially V- shapedimember having a'vertical arm '|46 and an upwardly and. rearwardly sloped arm |41. Af cartridgeIfeeding'Teslot 14| isprovided lon the forward ,verticalface of arm` |46 asshown in Eigs.,.1;and47. vOn the back face-ofthe rearwardly "sloped'a'rm`l4lY of' breech -block |46 there isgprovid'eda T-.shapedriblIllZ (Fig. 24) which slidably Iconnects breech block |46 with the breech block 'carrier |525V asfwill-be described later. A 'plurality vof `integral outwardly kprojecting locking lugs` |43 (Fig. 123) f are provided von the sides iofverticalu'arm .|46which engage corresponding flugs .inubarrelxextension |156 las willV be described. The rear edges of lugsMSare 1sloped fslightlyzas shown `lat f443a e to iacilitatecengag ment of such lugs with thelocking lugs in barrel extension |50. Near the bottom of breech block |40 there is provided a rearwardly opening, counterbored, horizontal hole |44 of suitable shape to receive a firing pin |45.

Firing pin |45 (Figs. 46 and 54) is provided with an integral head |48, the rear end surface of which is sloped as shown at |49 for a purpose to be described. A spring surrounds the body portion of firing pin |45 and abuts head |43 and the bottom of the counterbored portion of hole |44 to bias firing pin |45 rearwardly, thus retracting the forward end of such firing pin from the face of cartridge feeding T-slot |4|. A longitudinal slot (not shown) is provided in the head of firing pin |45 which is engaged by a transverse pin provided in breech block |40 (not shown). A hole |53 is provided in breech block |40 as shown in Figs. 23 and 25 to receive such transverse pin. Such pin is provided to maintain the sloped end |49 of firing pin |45 in the position shownin Fig. l. The firing pin is retained within hole |44 of breechl block |40 by a dovetail plate |66 which is inserted in a corresponding transverse dovetail slot |61 in the rear of breech block |40. A sloped rear corner |68 is provided on firing pin |45 which strikes against plate |66 thereby limiting the rearward travel of such firing pin.

A horizontal longitudinal hole |54 (Fig. 47) is provided near the top of Vertical arm |46 of breech block |40 and a cartridge detent |55 is inserted therein. An integral head |56 is provided on the rear end of detent |55 while the forward upper end of detent |55 is suitably beveled as shown at |51 so that such detent will be cammed rearwardly to permit a cartridge to freely enter T-slot |4| when the breech block |40 is raised to the locked position.

Detent |55 is likewise provided with an arcuate surface |55a on the underside of the forward end of such detent which engages the rim of a cartridge. As will be described, during unlocking of the breech block 40, such block drops vertically until the arcuate surface |55a of detent |55 strikes the rim of the cartridge. Breech block |40 is abruptly arrested with the lugs |43 thereof in alignment with the openings of barrel extension to permit disengagement of breech block |40 from such barrel extension. This will be described in more detail later.

A slot |56 is provided on the underside of head |56 in which is inserted a ilat spring |59 to bias detent forwardly while at the same time holding such detent in proper alignment. A lever 5|0 is pivotally mounted on head |56 of detent |55 by a pin 5|| as shown in Fig. 3. Such lever is bifurcated to surround head |56 and the function thereof will be later described.

A lower cartridge detent |60, similar to detent |55, is inserted in a hole |6| suitably spaced from hole |54 so that detents |55 and |60 will securely yet yieldingly hold a cartridge therebetween as will be further described. Lower cartridge detent |60 is likewise provided with an integral head |62. A shelf portion |63 produced by a fiat milling cut is provided on the head |62 of detent |60 on which is placed the other end of spring |59 to bias the detent |60 forwardly into the cartridge feeding T-slot |4I. Spring |59 is supported at its center section by a pin |64 inserted in a suitable hole |65 midway between detents |55 and |60 in the vertical arm |46 of breech block |40.

A third cartridge detent |69 is positioned somewhat below the detent |60 to prevent the fired cartridge case from working back up the T-slot, and further to arrest the downward movement of the breech block |40 relative to the carrier |25 at an unlocked position relative to the barrel extension |50 when no cartridges are in the feedway, as will be later described. The cartridge detent |69 comprises a plunger having an integral head |10. The detent |69 is inserted within a horizontal hole |1| extending rearwardly from the face of T-slot |4I. The forward portion of hole |1| is counterbored to accommodate the head |10 of detent |69. A helical spring |12 surrounds the detent |69 and is placed adjacent head |10. The spring |12 is likewise placed within the counterbored portion of hole |1| and thus biases detent |69 forwardly. Detent |69 is retained within hole 1| by a transverse pin |13 which engages a `notch |14 in detent |69. The upper corner of head portion |10 of detent 69 is sloped as shown at 360 to permit a loaded cartridge case to readily slide downward over such detent. The lower edge of head |10 is formed at right angles to the axis of detent |69 to effectively stop the upward travel of an empty cartridge case in T-slot |4| as previously mentioned.Y

A breach block stop |16 is secured to the inclined arm |41 of breech block |40 near the top of such member as shown in Figs. 1, '1 and 44 by a screw 11. The stop |16 comprises a substantially rectangular member provided on the right side thereof with a downwardly projecting lug |18. An upwardly sloped surface |19 is provided on the lower forward corner of lug |18 to clear the breech block carrier |25 as will be described. A rear surface 30 of the downwardly projecting lug |18 engages an integral lug |35 on breech block carrier |25 as will be later described. An upwardly projecting lug |8| is provided on the other end of stop |16. The lower corner of the upstanding lug |8| is arranged to be 'engaged by a breech block depressor 200, to be described, to retain breech block |40 in the raised position shown in Fig. 1.

Near the top of sloped arm |41 of breech block |40 there is provided a hole |82 (Fig. 9) in which is inserted a detent |83. The detent |83 comprises a plunger having a stem portion |84. The detent |83 projects somewhat beyond the T- .shaped rib |42 and is biased outwardly in such direction by a spring which surrounds the stem portion |84 of detent |83. The hole |82 isy counterbored to accommodate the spring |85 and the extreme end of such counterbored portion is ithreaded and a screw |86 is screwed therein to retain spring |85 within the hole` |82. The detent |83 cooperates with a recess |83a, on the carrier |25 to retain the breech block in an elevated position on the carrier while the barrel travels forwardly after unlocking, as will be later described in greater detail.

The breech block carrier |25 comprises a horizontral arm 26 and an integral upwardly inclined arm |21 as shown'in Figs. 1 and 45. Integral projecting longitudinal guide ribs |28 are provided on each side of the horizontal arm |26 of breech block carrier |25 to slidably mount such carrier inthe guideways 35 in the side plates 2 and 3. A transverse hole |29 is provided in the v lower rear `corner of carrier |25 as shown in Fig. 1 1n which 1s inserted a pin |30 to connect the breech block carrier |25 with carrier slide 63.

as will belater described.

On the Yforward face of the inclined arm 21 of carrier |25 (Figs. 1 and 54) there is provided sarcasme breech 'block relative to 'thercarri'en vAlong the 2 Lbottom of vTeslot |`35| inarm .|2.1, a longitudinal rectangular recess .|32 is provided to slidably mount .a hammer |33. The hammer |33 4is a substantially rectangular `member provided with 4an integral lug .|134 on theiupper .surface thereof .fas` shown .in Figs. 1 iandze. The lug |34 hasa sloped, :forwardly facing surface |36. When hammer |33 is placed within recess |32, :the `sloped .surface .il-36 `on klug |.:3i4 a'nates sldped surface `|49 4on .the end :of .firing .pin |45. A rearwardly opening' hole :I 3.1 provided inhammer |33 along the vlongitudinal .axis thereof, houses a `eheli'cal .hammer .spring |38. The spring .1;38ris retained within hole L31 by .a .headed rod-.like member |181. The headportion 'of the member .|811 :restson top of .inclined arm |21 toseal the V:end of a hole :|188 vwhich communicates with the lrectangular recess |32. The member '|81 is rev- :tained awithin .hole lll-88 by .a pin |89 inserted in :.atransverse hole 90 :near the `top of .the inclined :arm |21 of .carrier 5| 2.5.

The lower end v of hammer L33 is biffurcatedas :shown at .|39 in Fig. `1. It should be `mentioned here 'that :hammer 43.3 is .substantially shorter lzthan ithe .rectangular recess `|132 to .permit 'con- -siderablelongitudinal movement of .hammer |33 within such recess in order that hammer .|.3f3

can obtain sufficient momentum to strike -ring .pin |45 a smart fblow.

yA horizontal longitudinally 'extending hole |f9| -is Aprovided in the horizontal `arm |26 of -breech block'carrier 1| 25 to `house a sear |92. The sear |92 is a substantially Ycylindrical member zprovided on the rear -end with an integral tang :|93 v(liigs. 3 and 39) 'disposed at right angles to ifo `the axis of .the cylindrical body of such sear.V

The tang |93 projects outwardly somewhat -be yond the `side of carrier |25 through a suitable horizontal slot :in such carrier. Sear |92 is arranged -to be biased forwardly jby a .spring |95. This spring |95 is contained within a rearwardly opening, hollow bore |96 to sear -|92. The sear |92 and `sear spring |95 Vare retained within the hole |9| by arplug .|91 inserted in the lrear end -of hole 19|. Plug |91 `is retained in the Aposiftion shown in Fig. 1 by .-a lpin |98 insertedin a suitable vertical hole at the rear of arm .|25. The -forward end ofAsear V|92 is provided Vwith a `notch 8 A(Figs. v1 and 39) so that theend ofhammer |33 can be engaged .by :such end and .retained-thereon until released, as will be described later.

'The ycarrier slide 53 (Figs. .1 and 48) `is asubstantially rectangular integral member and is skeletonized so that such member comprises two comparatively .long bars 11 joined at 4their vforward endby across member `1.8 .to which .is .connected the carrier actuating rod 62 as pre- `vously described. .The .two bars 11 are .joined at their rearend .by a cross member 19. .In--the center of the cross Vmember A19 there 'is provided .an integral lug 80 which is substantially rectangularin conguration and enters a suitable recess '8| .provided on the underside of Icarrier |25. Carrier slide 83 Sis connected .to .breech block carrier .|25 by .the horizontal transverse pin '[38 yas previously described.

The hammer .|33 .is cocked bya cooking member `82. VThe cooking 4member 8`2...is.a .substantially triangular member and fis .inserted .in a

.210 .slot 284'proyided onV the undersideof carrier .1125. ducking member 82 J'i's pix/lotally mounted mithin =a:slot 8H on la itransverse pin rv83. :The

iatransverse1pini83 fhcuizer is @of rectangular con- ;guration whe're `such `gpinipasses 'through cock- .ing member 82. A :rectangular `hole 85 of ecciurse .providedainscocking .member '82 to :accom- -modaite such rectangular :portion :on :pin .83.

:Qne .olf :the .aapeXes A:8.6 .of'ccocking .member 82 apas's'es between the bifurcated rend .|39 zofchamvmer |33to force hammer |33 upwardlywhen'th'e vlower :apex 821 df'icccking Ymember .82 fstrikes fthe sldpedisurface .P261 ionthe upstanding lug 26 .pro- :v'ided on bottom plate 1:6 as carrier .|25 moves rearwardly.

:There is piyotally secured to the left .end .of pin .83, as .shownaiin Fig. 210., a rng @in iile'lifing levela 88. Lever 8.8 is secured to .pin f83 .1in .such -I-ashion fas to permit fflimited pivotal movelug ..89 iis provided :on the -end of pin .'83 which rests :within aisubstantially V-sha'ped recess 19|) fprovidedfon `the lend oflever K88. Afleaf spring V`'H15 :is -secureld .within .a :suitable .recess zin Athe @underside of cross .member 1:9 ;of carrier. .slide S3. Leaf spring 8 extends forwardly and iis provided with a .rounded end -|:|9 as shown in versely `outwardly projecting -lug f9| :to enga-ge A.therear .end of-operating slide SI1-5.

.The operating :slide .|15 (Figs. 1, g2 and 43) `essentially comprises a :rectangular bar. Near therear :end l.of Ysuch bar there are provi'ded two horizontal, .foppQsitely disposed, integral lugs :92 ,which -.engag e Vthe .slides V:of T-slot r:3:1 provided in the iside-,plates-2f- .A bracket :.93 haring; an Linl:tegral downwardly gprojectin'g lug 94 is secured to the Tforward :endl-.of the operating `slide |15 .as by twQ-:rivetsfs Integral 4lugs 19B oppositely .disposed =to onefanother f-are provided on the edges of bracket 93 `:to :likewise `engage the in- .side'edgesfof T-.slot 131'. The :wallsof T-sl'ot 31 are cut .away as g-shownfat 91 to permit assembly .of e operating :slide,;| 1f5 to 'F-sloti-31.

An operating slide actuator 98 is pivotallyse- .cured .to the downwardly projecting lug -94 'as by -a .pin;-99. :Actuator 98 :comprises sa 'rectangular .bar which vis preferably skeletonized as shown in Figs. liandaforflighteningzpurposes; ,Therea'r fend Y'of :actuator 98 zslidably :retained within .la bracket 18 underneath fthe receiver as shown in ,5. A :hand-1e I|182 rcomprising ,a'short .tubular member lisssecurediteoperating slide actuator 98 bya (chain |83 `-:to .fa'cilitateim'anual retraction of actuator 98 -and operating `'slide -|f1;5 as will be later described. .'Iheureariend fnf Aoperating Slide A15 is provided r.with `sloped .surface L04 which cooperates with firing epin fnetracting flever 88 .as previouslyrmentioned; Sloped surface l 84 terminates .in a vertical shoulder 2|21| as shown in Fig. a3;

Operating'slide .If-1.15 :fis provided .to :manually charge or. load Ethe frearm. Such .slide Llikewise provides means afor retracting fthe v:tiring .pin as ;will=b.'e presentlydescribed. quitezn'ecessary finuthefeventlafmisre should. occur. .will berbrought .out VVlater,if.theractiorl ayer'ezretracted without retraction lof fthe iiring {.pin, fthev breech ..76 block |48 would slideidownithe'breech'blockcar# rier |25 and thus break the tip of the firing pin.

When operating slide |15 is retracted rearwardly by means of handle |02, the sloped end |04 of operating slide |15 strikes the lower corner of lug 9| of firing pin retracting lever 88. Upon striking the end of such lug, cooking member 82 is forced upwardly a slight amount which likewise forces hammer |33 upwardly. This upward movement of hammer |33 lifts lug |34 from the head |48 of firing pin |45. Firing pin |45 is then retracted by the bias of spring until the sloped corner |68 provided on the underside of head |48 strikes the plate |66. The forward end of ring pin |45 will then be sufficiently retracted from the face of breech block |40 so that there will be no interference with the cartridge in the T-slot |4| of breech block |40. As the sloped surface |04 on the end of operating slide |15 strikes lug 9|, lever 88 is raised upwardly along such sloped surface until the extreme rear end of lug 9| strikes shoulder |2| provided on operating slide |15. Upon striking shoulder |2|, the lever 88 is prevented from rotating further and hence carrier slide 63, carrier |25 and breech block |40 will be moved rearwardly by operating slide |15.

As the recoil stroke is completed, cooking member 82 rides up cam surface 21 of lug 26 and hammer |33 is raised upwardly suiiciently to permit sear |92 under the bias of spring |95 to slide under the bottom end of hammer |33 thus retaining hammer |33 in the cocked position.

The carrier latch |00 (Figs. 1 and 3) as previously mentioned, is pivotally mounted between lugs 28 on rear bottom plate 6. On the rear end of carrier latch |00, on the upper surface thereof, there is provided an upright bifurcated integral lug |05. Rear corner |06 of lug |05 is suitably shaped to engage a shoulder |01 provided on the underside of carrier |25 for the purpose of retaining carrier |25 in the extreme rear or reooiled position as will be later described. Carrier latch |00 is pivotally mounted between lugs 28 on bottom plate 6 by a transverse pin |09 supported in suitable holes 29 in the lugs 28. A spring ||1 is provided to bias latch |00 upwardly into the path of carrier |25. One end of spring ||1 is placed underneath the rear end of latch |00 Within a suitable recess while the other end of spring ||1 rests in a suitable recess in the top of rear bottom plate 6.

A carrier latch release member ||0 is pivotally secured to the forward edge of carrier latch |00 by a transverse pin The latch release ||0 is bifurcated to permit such member to surround lug 26 on bottom plate 6. The latch release ||0 slopes downwardly and forwardly as shown in Figs. 1 and 8 and terminates in a toe portion |2. A recess |2a is provided in bottom plate 1 to receive toe portion ||2 when such toe portion is forced downwardly as will be presently described. The release ||0 rests on the top of the downwardly sloped portion 25 of bottom plate 6 as shown at ||3. The point of contact at ||3 acts as a fulcrum so that when breech block |40 slides down on breech block carrier |25 and strikes the toe ||2, carrier latch release ||0 will be depressed thereby releasing carrier |25. Immediately forward of the toe ||2, a recess ||4 is provided in forward bottom plate 1 in which is placed an insert ||5 preferably of hard fibrous material to cushion the impact of breech block |40 as the breech block drops downwardly as will be later described. The insert ||5 is secured to bottom plate 1 by a screw ||6.

A breech block. depressorv 200 is 'pivotally mounted on the left side of breech block carrier |25 as shown in Figs. 5, '1, 8, 9, and 10. The breech block is arranged Vto be disengaged from breech block carrier |25 by the breech block depressor 200 at the desired time, as will be later described. The depressor 200 comprises a body portion |22 having in the center thereof an integral upright arm |23. The extreme upper portion of arm |23 is bent forwardly somewhat as shown in the above figures, and a notch |24 is provided in the uppermost Vcorner thereof to engage lug |8| of stopV |16.

Depressor 200 is fixedly secured to the left hand end of a transverse pin |99. Pin |99 is journaled within a transverse hole 20| in breech block carrier |25. A latch 202 is xedly secured to the right hand end of pin |99 and adjacent the outside of carrier |25 as shown in Fig. 3. The bottom surface of the body portion |22 of depressor 200 rests on the top surface of the horizontal arm |26 of carrier |25. The forward edge of body portion |22 is rounded as at 203 to permit rotation of depressor 200 about the axis of pin |99. A plunger 204 suitably spring biased is vertically mounted within a suitable downwardly opening hole in the rear edge of body member |22 to bias the arm |23 in a counterclockwise direction to insure that notch |24 will engage the lower corner of lug |8| of stop |16. A roller 205 is mounted on a xed stud 2050i on the side of body portion |22.

A depressor bar 201 (Figs. 5, 7, 8, 9, 10) comprises a substantially rectangular bar slidably mounted on the left side of the gun for reciprocating longitudinal movement. On the forward end of depressor bar 201 there are provided two transversely projecting, integral lugs 208 (Fig. 3). A latch 209 is pivotally mounted between the lugs 208 on a suitable pin which is supported by lugs 208. Latch 269 is biased inwardly against barrel extension |50 by a suitable spring (not shown). The latch 209 engages a stud 2|| (Figs. 5, 8, 10) provided on the side of barrel extension |50 to carry depressor 201 forwardly as will be presently described.

On tcp of depressor bar 201 an overhanging rib 2 |2 (Fig. 1) is provided which engages the top surface of side plate 2 to provide bearing support for bar 201. An upwardly sloped cam surface 206 is formed on a vertical lug 2|`3 provided on the rear end of rib 2|2. Lug 2|3 also projects inwardly as shown in Fig. 3 so as to engage roller 205 on depressor 200. An overhanging shelf 2|4 is secured to an integral raised lug 2|5 on depressor bar 200 by two rivets 2|6. The lug 2|5 is preferably slotted and the shelf 27|4 is inserted in such slot prior to riveting. The over-hanging shelf 2|4 projects over the forward end of cam surface 206 and is provided to engage roller 205 to disengage depressor 200 from lug |8| thus permitting breech block |48 to become disengaged from barrel extension |50. Two longitudinal slots 2 |1 and 2 I8 are provided at the rear and forward ends of depressor bar 201 through each of which is inserted a screw 2|9. A washer 220 is placed under the head of each screw 2|'9 which bears against the side of depressor bar 201 to provide increased bearing support. Screws 2|9 are screwed into suitably threaded holes in side plate 2 and are so tightened as to permit free longitudinal movement of depressor bar 201 within the limits of slots 2|1 and 2|8 on side plate 2.

The barrel extension |50 (Figs. 1 and 49) com- 7'6 prises a substantially rectangular block. A vrtical 'IT-Slet 212,1.- (Fie.- wi-.ispr-,Qvided .ini thefrear portion of barrel extension |50. A threaded hole 2.2.2..-"mmi1ncetes .between the. front face ofharrelvextension liland the.back. of-Tslot 22 The breach end of lbarrel 50,V is screwed; .into threaded hole-12,22 asgshown in Fig.; 1. Two parallel intev gral ribsA 223 are provided onvthe bottom surface ot barrel extensior-1|513;v whichengage the guide- Ways 35'provided in eachV side plate 2.and 3.. A plurality of integral;locking'1ugs224 vare provided oneach side of `Tslot22| vvhichare engagedby thelocking lues on breech ;blo ck.|40; The` front edges of-lugs 224 Yare slopedforwardly from the bottomv to the top inworder to permit ready: entry 0.1? breech blockV lugs |43; intoT-'slot 22|' and yet Apermit snug` engagement with rear edges |43a When the upward vmovement ofbreech. block |40 iscompleted..` Acartridge. support 225.is cen.A tral-ly secured to the. top. of barrel extension |50 by a screw 226 as shown in Fig. l.

A'threaded sleeve.221 is. screwed onto the. barrel as .shown in Fig. 2; Sleeve..221 has an integral downwardly projectinglug228 which engages an; annular groove 229 provided on the head of a piston rod 230fwhichi projects out or .tube 38.

Afeedway 23| is transverselymounted on` top of sideplates 2 and S'and; substantially comprises aghorizontal shelf 23221:(Figs. 20 and 29). A large rectangular depending portion 233 is-.provided on` the'underside of shelfportion 2321iwhich is ,bi.` turcated; by. a semi-.circular cut `235.1to. permit the feedway 23|v to. be. lowered over. barrel 5|]v as will be. presently described.. A rectangular recess. 234 is provided in the rear depending. portion. of 233 (Fig.v 29). to. permit the. barrel extension |50 to slide. forwardly underneath shelf. 232 a short distance. Two oppositely disposed lugs 246y are. formed by the semi-.circular` cut 235.. each of which isbifurcated as shownA at 24.1 (Fig. 22) and. a. longitudinal` hole 2418. is provided in. each ofthe. lugs 246.. A broad. T-'slot 2:36'. (Figs. 21 and 22)v parallel .to` the longitudinalsides of..shelf portion. 232 is.l provided onthetop of .such shelf portion to receive a cartridge strip 231 to be presently described. A raised rib1238is centrally provided. on-the bottom of Tslot 236101q a purposeto be described. An integral substantially cylindrical housing 239 is provided on the left side of feed-. way-23| as shown in FigsdZO and 29.` The cylindrical housing 239contains a springI tape 260'. for actuating the cartridge strip 231.

Feedway 23| is pivotallymounted on the-right side of the rearm by a bracket 211|Y (Fig. 50). The bracket 24| is placed within. a suitable vertical slot (not shown) on side plate 3 andis se-r cured thereto preferably by suitable screws. An

integral lug 244 is provided on top of bracket 2M. and a longitudinal hole 245 is providedfin such. lug. The right-hand lugs V2|6of thefeedway are.-

placed over lug 244 of: the bracket 22| and-a pin 240 is inserted through hole 248 and hole-245cm:

PinV 259 is suitably-secured withinvided therein. A longitudinal slot 255.(Fig. 17),

communicates with hole254-toper1nit a `f eedway 'such Acover and winding spring 219 aswill be releasepm v256v to-enter-thereinas will be prese ently described.

VifslienyfeedwayV 23 is rotated .into position over barrel 50,- the bifurcated left-hand lug 246 of the feedway engages lug 2'53 .on bracket 250 thereby aligning holes 254and .2.48.as shown in Fig. 5... Feedway release. pin 256comprises a pin 251 havingan integral head 25.8. A flat milled section 2.59.' is, provided in the centerofpin 251 of slightly lesser width thanslot 25.5; on. lug 2,53 of bracket 250;; Thus pin25tl enters hole 25lithrough slot 2'55'.. When .pin 256 is rotatedv counterclockwise feedway 23| is locked to bracket 259. A suitable recess. 260is provided on the top ofthe rear edge offshelf portion 232 to` accommodate the cartridge suDpQrt 225;..and to provide clearance for breech blOCkQ.

A longitudinal hole 26| (Figs. 20 and 22) is pro-f vided inthe portion 233 underneath shelf portion 232 in which is-inserted a cartridge strip retaining plunger 262;; The plunger 262 comprises a hollow: tubular. member having ari-integralupstanding head v263Ay at the forward end thereof. Head263-rests within a suitable recess 26d in the lQftvhandedgevof T-slot 23,5. A helical spring 265 is p lacedywithin theV hollow interior of plunger 2 2 i;and is retained therein by a cylindrical member 2 66.k Such member is in turn retained bya pin 26;] inserted inv a vertical holeV in the bottorn of `T-slot 236 and in turn passes through a slotted hole 26E-in plunger 262 thence through a suitable holeinfcylindrical.member 266. Limited longitudinal movement of plunger 262 is thus provided bythe slotted hole 269. Spring265 biases the headless end of plungerr262 into the rectangularrecessv 234 and` head` 253into the path of the-cartridge strip` 231 as will be described. TheV endofplunger 262 projecting into recess 23d is struck by the forward face of barrel extension |50V` for the purposey of pushing head 263 of plunger 2 62v out of the path of strip 231 to permit feeding another round into the action ofV the firearm as will be` later'. described.

Thecartridge strip actuating tape '240 is wound about a spool 21| which isl inserted within cylin. drical; housingV 23S. Thespool 21| is provided with an integral ange 212 to retain tapeV 240 on such spool, as shown in. Fig. 21. A spindle 213. isv provided. for mounting spool 21|. Such spindle has anintegral head 21dV which is rotatably supported bythe rear wall o. cylindrical housing 23S. Adjacentspool; .21| a squared portion 215.15 provided on spindle .213 and upon such squared portion a hub `216 is placed. A spring retainer 211 of thesame diameter asspool 21| is inserted within housing 239 and likewise placed adjacent spool 214| .e Two integral outwardly facing oppositely disposed lugs 2181 are provided on. retainer 211. One end of a flat. clock-type springZQ is secured tohulo216` insuitable fashion while the other .end ofjspring' is secured to retainer 211 by means of aV rivet 280.. Spring 219 is arranged to be wound by a disk-like cover 28|. An integral knob 282`having a knurled outer surface is centrally providedon the cover 28| to facilitate turning presently described.

An axial cylindrical recess 2B3-is provided on therearfend of cover 28|y to support the forward endgof-tape 240iis securedto spool21.| by passing thatend of suchl tape about a pin 210 and insert-.f ling the tape and; such pin ina transverse slotted,

l hole '284 in spool 21| as shown in Fig. 20. The tape 240 is then wound about spool 21|. The other end of tape 240 is passed along the bottom of a longitudinal T-slot 285 provided in rib 238 of feedway 23| where it connects with a strip actuating slide 286. Slide 286 comprises a base 281 conforming in shape to the T-slot 285 and an integral lug 288 provided on the top of such base. The right hand end of base 281 is rounded as shown in Fig. 20 and the end of tape 240 passes around such rounded end and is secured to such slide in the same manner as to spool 21 I. A slot 289 is provided on the underside of lug 288 as shown in Fig. 20 which engages the end of cartridge strip |31 as will be presently described.

The cover 28| is restrained against turning by a locking spring 29| (Figs. 3, 5, 21 and 53) which comprises a rod-like member having one end or" reduced thickness. On the underside of such spring there is provided an integral projection 292 which engages a slot 293 on the top surface of knob 282. 'I'he rod-like portion of spring 29| is inserted in a hole 294 in feedway 23| as shown in Fig. 5. The projecting end of spring 20| is turned upwardly for convenience in grasping as shown in Fig. 53. To place clocktype spring 219 under tension, spring 29| is raised to disengage lprojection 292 from slot 293. Knob 282 may then be turned in a counterclockwise direction as shown in Fig. 21 until spring 219 is under the tension desired. When spring 219 is placed under tension, such force is transmitted to spool 21| and in turn to tape 240 for actuating cartridge strip 231 as will be lpresently described.

The cartridge strip or cartridge feed member 231 comprises a shallow, channel shaped member having outwardly flared sides 295 which rest within T-slot 236 as shown in Fig. 21. A plurality of cartridge clips 296 comprising substantially semi-cylindrical tubes are secured to the top surface of strip 231 as by rivets 291. The clips 296 are tapered as shown in Figs. 3 and 19 to conform to the taper of a cartridge case 300. The sides of clips 296 engage somewhat more than half the periphery of each cartridge 300 as shown most clearly in Fig. 21 to securely, yet yieldingly, hold such cartridge case. An integral spring positioning detent 298 is provided on the rear end of each clip which is suitably formed to ilt Within an extractor groove 299 provided at the rear end of each cartridge 300 and strike the inside of the rim of each case 300 to align the bases of the cartridges in strip 231.

A plurality of wedge-shaped notches 30| (Fig. 19) are provided on the forward edge of each strip 231. The notches 30| have the same spacing as cartridge clips 296 and are provided to be engaged by the head 263 of cartridge strip retaining plunger 262. The cartridge strip 231 is inserted into the feedway from the left side of p the firearm as shown in Fig. 3, the flared sides 295 engaging T-slot 236. The right end of cartridge strip 231 then engages slot 289 on the underside of lug 288 of slide 286 thereby unreeling tape 240 from spool 21|. Thus tape 240 biases strip 231 to the left to bring each cartridge 360 into feeding position. A cartridge stop pawl 302 is pivotally mounted in the upper left-hand corner of ieedway 23| as shown in Figs. 3, 19 and 51 to arrest and to align each cartridge in the feedway. Such pawl is pivotally mounted on a pin 303. A spring 304 is inserted within a suitable slot to bias one end 305 of 16 pawl 302 upwardly into the path of a cartridge 300.

A wedge-shaped sear release member 306 (Fig. 34), which has a T-shaped base 32|, and a trigger 301 are mounted on a bracket 308 on the right side of the rearm as shown in Figs. 3 and 17. The bracket 308 is suitably secured to side plate 3 slightly ahead of sear tang |93 as shown in Fig. 3. A grip 309 is vertically mounted in bracket 308 as by a. bolt 3|0. The trigger 301 substantially comprises an L-shaped member as shown in Fig. 35 and is pivotally mounted on bracket 308 by a vertical pin 3| The forwardly projecting leg of trigger 301 is provided with an elongated hole 3|2 which is engaged by a vertical pin 3|3 in a sear release housing 3|4 as shown in Figs. 36 and 37. Pin 3|3 also passes through wedge shaped sear release member 306 thereby pivotally securing such member to housing 314.

Housing 3|4 is a substantially rectangular member and is mounted in a T-shaped slot 3|5 provided on top of bracket 308. A transverse slot 3|6 is provided on the left hand side of housing 3|4 to receive a Sear release plunger 3|1. Sear release plunger 3|1 is a T-shaped member provided with a cylindrical stem portion 3|8 (Fig. 38). A spring 3|9 surrounds the end of stem portion 3|8 to bias plunger 3|1 outwardly. A spring-biased plunger 320 (Fig. 3) is inserted within a suitable hole in bracket 308 and engages the front surface of trigger 301 in such fashion that trigger 301 will be biased in a clockwise direction about pin 3| l.

The trigger mechanism illustrated in the appended drawings is utilized for semi-automatic fire. When the action is in the breeched or closed position shown in Fig. 3, sear |92 is released by pressing against trigger 301. Sear release member 306 which is pivotally secured to housing 3| 4 is forced transversely across a tajered transverse slot 500 on the top edge of side plate 3. The Wedge-shaped nose of sear release member 306 then wedges between sear tang |93 and breech block carrier |25 urging sear |92 rearwardly thereby effecting release of ring pin |45. The rearward movement of carrier |25 then rotates release member 306 rearwardly against the rear surface of tapered slot 500 whereupon such carrier and in fact the whole breech mechanism slides past such release member.

When the barrel extension has recoiled past the sear release member 306, plunger 3|1 biases such member outwardly into the path of barrel extension |50. It should be mentioned here that the T-shaped head of plunger 3|1 contacts some portion of base 32| of release member 306 at all times. Thus regardless of what position the release member 306 may assume, such plunger will force member 306 to the position shown in Fig. 3 when the trigger is released as will be presently described. As the barrel extension |50 moves forwardly on the counter-recoil stroke, such extension strikes sear release member 306 rotating such release member forwardly until it strikes the forward sloped surface of tapered slot 500, whereupon the breech mechanism will slide freely past sear release member 306. As the sear release member 306 has been thrust to one side, as just described, the weapon cannot be fired automatically, the sear release member having been disconnected from the sear |92. To again rire the weapon the trigger 301 is pushed forwardly whereupon housing 3M is forced away from the gun through the connection of such 

